1. Field of the Invention
The present invention is generally directed to a hand dryer assembly for drying the hands of a user, and more particularly to a hand dryer assembly that includes an ionization assembly emitting charged ions into the moving air stream produced by the hand dryer assembly to sanitize the moving air stream, the surrounding air pulled into the moving air stream, the hands of the user, and surfaces of the hand dryer assembly and any surfaces adjacent thereto.
2. Description of the Prior Art
Wall or surface mounted hand dryer assemblies have been used for many years in washrooms, locker rooms, and the like for drying a user's hands after washing. Originally, most of these hand dryer assemblies produced a low velocity moving air stream, causing the drying process of the hands to be fairly slow. To speed up the drying process, many manufactures created high-speed or high velocity hand dryer assemblies. Both low and high velocity hand dryer assemblies are advantageous over traditional paper towel dispensers in several respects. Namely, hand dryer assemblies eliminate paper towel usage and its associated cost to the facility and the environment. Hand dryer assemblies promote low maintenance facilities as less trash is generated when paper towel use is eliminated.
Typical hand dryer assemblies that are known in the art generally include a backplate configured to be mounted against a support structure such as a wall. An outer shell is attached to the backplate with the outer shell including an air inlet for receiving ambient air disposed outside of the outer shell and a blower assembly is located within the cavity of the outer shell. The blower assembly generates a moving air stream which exits from a nozzle extending through the outer shell. Operation of the blower assembly is accomplished by either a push button disposed on the outer shell or a motion sensor detecting the presence of the hands of the user adjacent the nozzle.
Such hand dryer assemblies also present some drawbacks. Washrooms, by their nature, may contain unusually high amounts of bacteria, viruses, and other pathogens. These microorganisms and the like may contaminate the surfaces of the washroom as well as the ambient air even when the washroom is diligently cleaned. Hand dryer assemblies must operate within this hostile environment. Concern is that the moving air stream produced by the hand dryer assembly may contain high concentrations of airborne microorganisms since the hand dryer assembly draws in ambient air from the washroom. To address this problem, some manufactures have added various filters, including HEPA filters, to remove many of these microorganisms from the moving air stream.
The addition of the filter to the hand dryer assembly presents several drawbacks and may have a limited effect. First, filters must be changed periodically and therefore add to the maintenance of the hand dryer assembly. Second, as filters traditionally were not common, many facilities do not have procedures in place for regularly changing filters in hand dryer assemblies. All of the above add to the operating costs of the hand dryer assembly, well beyond the purchase price of replacement filters. Third, as many wall mounted hand dryer assemblies are placed in high use or high crime areas, they are manufactured to be vandal resistant, which makes changing the filter more difficult. Fourth, while traditional hand dryer assemblies that do not employ filters are fairly maintenance free, if a filter is not regularly replaced, the performance of the hand dryer assembly will degrade significantly over time and that may eventually damage the hand dryer assembly. For example, the restricted air flow caused by an old filter may cause the hand dryer assembly to overheat leading to failure of the electric motor or heating element. Fifth, as air movement is restricted through a dirty filter, the blower assembly may find ways to pull air around the filter instead of through the filter. Sixth, the filter blocks the free movement of the moving air stream so the blower assembly typically must be uprated to provide the additional suction necessary to pull the desired velocity and volume of moving air stream through the filter. Accordingly, such hand dryer assemblies typically have poorer performance and are less energy efficient.
Another problem with hand dryer assemblies that employ a filter to clean the moving air stream is that the filter may be largely ineffective. The applicant has found that for hand dryers employing a filter that while the moving air stream air that exits the nozzle is generally filtered, the air that hits the user's hands is less so. More specifically, the moving air stream pulls in ambient air after the moving air stream exits the air outlet of the hand dryer assembly. Since the moving air stream includes ambient, entrained air that does not pass through the hand dryer assembly or the filter contained therein, the filter does not significantly reduce the particles or microorganisms relative to filterless hand dryer assemblies.
Another issue with many current hand dryer assemblies, particularly high-speed hand dryer assemblies, is that spray water from the drying of the user's hands may accumulate on surrounding surfaces of the hand dryer assembly and the support structure such as the walls and floor of the washroom. This errant spray may carry microorganisms from the ambient air or poorly washed hands of the user and thereby contaminate and grow on these surfaces. Accordingly, what is needed is a hand dryer assembly that sanitizes the moving air stream, the hands of the user, and surrounding surfaces of the hand dryer assembly and/or the washroom.